Question

Super Easy Question! http://wug.physics.uiuc.edu/cgi/courses/shell/per/phys111/ie.pl?01/IE_v_vs_t#waypoint

I swear it is-- 2.5 m-- but it tells me I am wrong!

Answer 1

how you can be sure it is 2.5 ?
from t=0 to t=1.5, the velocity is increasing at constant rate, the slope in interval t=0 to t=1.5 is 6.666 m/s^2, that is your acceleration, using kinematic equations, the distance covered in first 1.5 seconds is 7.425 m

from t=1.5 to t=3, the acceleration is zero and velocity is constant at 10 m/s, using kinematic equations, the distance covered from 0 s to 3 s is 22.425 m

then it goes on constant negative acceleration of -6.666 m/s^2 for 1 s, but the velocity is still positive till fourth second, after second 4, v is negative for 1 second, so the distance covered in second 3 to 4 is negative of distance covered from 4 to 5, cancel them out, u are left with distance covered in first 3 seconds.

that is exactly 22.425 m

but the webpage accepts 22.5 m only